IBEX-lo 2015 Ops and ISN Overview
D. Heirtzler, A. Galli, K. Fairchild, H. Kucharek, T. Leonard,
E. Möbius, M.Quinn, N. Schwadron
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
1
2015 IBEX-Lo Overview
• Overall Operations
– IBEX has operated nominally during 2015 (so far)
• No abnormal HV behavior, PAC stable @ 7kV
• MCP responsiveness remains effectively unchanged from
previous years.
• One incident of “Orange” space weather conditions did not
adversely effect the instrument.
• The IBEX-lo low voltage current monitor follows count rates
and is an indicator for strong SEP events as well as normal
high backgrounds.
– Planning has begin for remainder of 2015/2016
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
2
IBEX-Lo MCP Gain testing
• Last run in orbit 267b
– Results normal, no indication of gain loss
This year’s gain test planned for Orbit 309 higher than 15 Re
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
3
IBEX-Lo Maps
• Currently there are 3 Map corrections
1. Geometric Correction
2. Bootstrap Correction
3. Oxygen Sputtering Correction
• Only 2 and 3 are implemented in the 5 year and
trial 7 year maps.
• Different corrections needed for different phases
of the mission:
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
4
ISN Goodtimes List
• The ISN goodtimes list has been updated
through orbit 279a
–
–
–
–
–
–
–
Orbit 9-26 (2009)
Orbit 54-75 (2010)
Orbit 102-123 (2011)
Orbit 147a-160b (2012)
Orbit 193a-198b (2013)
Orbit 233b-239a (2014)
Orbit 271b-279a (2015)
• ISN goodtimes expanded to include Warm
Breeze Orbits
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
5
2015 ISN Season Pointing (1/3)
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
6
2015 ISN Season Pointing (2/3)
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
7
2015 ISN Season Pointing (3/3)
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
8
ISN 512spin Data Products (1/5)
• For periods within the ISN goodtimes:
– Accumulated direct event data that meet the following
criteria:
1. Golden triples
2. “Hydrogen” time-of-flight
3. Energy Steps 1-3 are included during non-special mode
periods.
– Histogram bin data coincident with direct event times
above, accumulated into 512 spin periods (approx 2
hours)
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
9
ISN 512spin Data Products (2/5)
• ISN data products:
– For each contiguous time in the ISN goodtimes list:
• 1 row for each of the 60 6° anguar bins indicating the center
angle for a given bin
• Start time for each 512 spin period (GPS time)
• End time for each 512 spin period (GPS time)
• Total accumulation time (sanity check)
• Histogram counts for each angular bin
• Direct Even counts for each angular bin
– Data files are in comma separated value (csv) format
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
10
ISN 512spin Data Products (3/5)
• ISN data product sample:
angular bin
center
(sanity check)
GPS
Start time
angular bin
center
direct event
counts
histogram
bin counts
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
11
ISN 512spin Data Products (4/5)
• ISN data product QA checks:
– All ISN season orbits are checked for contaminating backgrounds
around the ISN peak itself. Times with high backgrounds are
eliminated.
• Background threshold for this test is determined orbit by orbit
using sample quiet times.
• Times when the TOF 2 rate exceeds this background by 60%
are excluded.
• Times with spin issues are excluded
• Times with special operations are excluded (gain tests, etc…)
– Remaining times are included in ISN data products
– Resulting ISN data products are checked for continuity (time and
angle), and suppression (loss of direct events due to instrument
throttling).
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
12
ISN 512spin Data Products (5/5)
• Sample ISN Background goodtimes determination
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
13
ISN 512-Spin Data Release
• ISN data for 2009 and 2010 have been released
to the public.
• ISN data for 2011 – 2014 have been released to
the team and will be released to the public
following the upcoming ApJS Special Section.
• ISN data for 2015 have been generated and
passed QA checks and will be released to the
team.
– 2015 data will be further validated during upcoming
science investigations.
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
14
ISN Suppression Issues (1/2)
• Some time periods show higher than expected direct event
suppression in the ISN peak.
Direct event suppression
between 55-70% in the
peak.
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
15
ISN Suppression Issues (2/2)
• Some time periods show higher than expected direct event
suppression.
D. Heirtzler et al, UNH/SSC
IBEX SWTM
August 2015
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